﻿#region Copyright (c) 2003 - 2008, Andreas Mueller
/////////////////////////////////////////////////////////////////////////////////////////
// 
// Copyright (c) 2003 - 2008, Andreas Mueller.
// All rights reserved. This program and the accompanying materials
// are made available under the terms of the Eclipse Public License v1.0
// which accompanies this distribution, and is available at
// http://www.eclipse.org/legal/epl-v10.html
//
// Contributors:
//    Andreas Mueller - initial API and implementation
//
// 
// This software is derived from software bearing the following
// restrictions:
// 
// Copyright (c) 1994
// Hewlett-Packard Company
// 
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee,
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation.  Hewlett-Packard Company makes no
// representations about the suitability of this software for any
// purpose.  It is provided "as is" without express or implied warranty.
// 
// 
// Copyright (c) 1996,1997
// Silicon Graphics Computer Systems, Inc.
// 
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee,
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation.  Silicon Graphics makes no
// representations about the suitability of this software for any
// purpose.  It is provided "as is" without express or implied warranty.
// 
// 
// (C) Copyright Nicolai M. Josuttis 1999.
// Permission to copy, use, modify, sell and distribute this software
// is granted provided this copyright notice appears in all copies.
// This software is provided "as is" without express or implied
// warranty, and with no claim as to its suitability for any purpose.
// 
/////////////////////////////////////////////////////////////////////////////////////////
#endregion


using NStl.Iterators;
using NStl.Linq;
using NUnit.Framework;
using System.Collections;
namespace NStl.NUnit.Support
{
    /// <summary>
    /// An abstract fixture to test any <see cref="IBidirectionalIterator{T}"/> implemenation.
    /// </summary>
    /// <typeparam name="T"></typeparam>
    public abstract class BidirectionalIteratorFixture<T> : ForwardIteratorFixture<T>
    {
        protected override IForwardIterator<T> CreateFwdBegin()
        {
            return CreateBidItBegin();
        }

        protected override IForwardIterator<T> CreateFwdEnd()
        {
            return CreateBidItEnd();
        }
        protected abstract IBidirectionalIterator<T> CreateBidItBegin();

        protected abstract IBidirectionalIterator<T> CreateBidItEnd();

        public override void SetUp()
        {
            base.SetUp();

            biditBegin = (IBidirectionalIterator<T>) fwdBegin;
            biditEnd = (IBidirectionalIterator<T>)fwdEnd;
        }

        protected IBidirectionalIterator<T> biditBegin;
        protected IBidirectionalIterator<T> biditEnd;

        [Test]
        public void PreDecrement()
        {
            IBidirectionalIterator<T> other = biditEnd.PreDecrement();
            Assert.AreSame(other, biditEnd);
            Assert.AreEqual(other, biditEnd);
            Assert.AreEqual(referenceArray[referenceArray.Length - 1], biditEnd.Value);
        }

        [Test]
        public void PostDecrement()
        {
            IBidirectionalIterator<T> other = biditEnd.PostDecrement();
            Assert.AreNotSame(other, biditEnd);
            Assert.AreNotEqual(other, biditEnd);

            Assert.AreEqual(referenceArray[referenceArray.Length - 1], biditEnd.Value);
        }
        [Test]
        public void IterateBackwardsAndReadValue()
        {
            ArrayList target = new ArrayList();
            while (!biditEnd.Equals(biditBegin))
            {
                biditEnd.PreDecrement();
                target.Add(biditEnd.Value);
            }

            biditEnd = CreateBidItEnd();

            ICollection expected = Reverse(biditBegin.AsCollection(biditEnd));
            CollectionAssert.AreEqual(expected, target);
        }
        private static ICollection Reverse(ICollection c)
        {
            ArrayList l = new ArrayList();
            foreach (object o in c)
                l.Insert(0, o);
            return l;
        }
    }
}
